Select the correct answer.
If a line crosses the y-axis at (0, 1) and has a slope of `4/5`, what is the equation of the line?

A.
4y − 5x = 5

B.
y − 4x = 5

C.
5y + 4x = 5

D.
5y − 4x = 5

Respuesta :

Answer

D.  

5y − 4x = 5


Explanation

The general formula of a line function is;

y = mx + c

Where m is the slope and c is the y-intercept.

From the information given;

m = 4/5

c = 1

y = (4/5)x + 1

5y = 4x + 5

5y - 4x = 5

For this case we have, by definition, the slope-intercept equation of a line given by:

[tex]y = mx + b[/tex]

Where:

m is the slope

b is the cut point with the y axis

If we are told that the line crosses the axis and in (0,1), we have that[tex]b = 1[/tex]

In addition, they tell us that [tex]m = \frac {4} {5}[/tex]

Substituting in the generic equation we have:

[tex]y = \frac {4} {5} x + 1[/tex]

This is equivalent to:

[tex]y-1 = \frac {4} {5} x[/tex]

[tex]5 (y-1) = 4x\\5y-5 = 4x\\5y-4x = 5[/tex]

Thus, the equation of the line is: [tex]5y-4x = 5[/tex]

ANswer:

Option D


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